Topic: Cylinder install CB550K

[Fraserimoore]

Hi Guys,

I'm really struggling with getting the cylinder barrels over my pistons on my 550. (Engine in frame)

All pistons are standard with new standard rings.
The cylinders have been honed.

I've put 2-3 to TDC and lowering the cylinders down onto the pistons with rings compressed. I can get the top 2 rings in but then it won't go any further?

Any advice/suggestions would be much appreciated.

NB. I thought I'd also take one piston off along with the barrels to see if it could fit it with it being off the con rod.  But even installing one I get the same problem. The piston will spin freely with the 2 top rings in the cylinder but once again it will go no further???

Thanks again

[JBMorse]

Is the cylinder assembly bumping something else, causing it not to slide down? Or are you sure the cylinder is actually over the rings, and not resting on the oil ring on one piston?
I remember mine requiring a little force once pistons 2 and 3 were in, to get the jug lowered the rest of the way. Others can correct me, but I think a gentle tap with a soft mallet is okay here.

[Fraserimoore]

It could potentially be resting on the oil rings... maybe the tool isn't tight enough and not compressing them fully?

I've given the jugs a good tap once I get to that point and they don't budge, but then again the oil rings are still in view.

[flatlander]

it should not take too much effort if everything is aligned correctly, just a bit of pushing down the cylinder block.
actually, you can compress the rings by hand and use the taper at the bottom of the sleeves to guide them in, even without compressor tool.

are the pistons straight and not tilted when entering?

[Fraserimoore]

Thanks for that image flatlander.

I was aligning the pistons by hand, I think I'll wedge some wood under them as per your image to see if that helps me.

Will update once I've had another go.

Thanks

[BomberMann650]

A question if I may; what is ring gap exactly?

[Fraserimoore]

Ring Gaps are as follows (I lost the paper with the oil ring gaps so this only shows the top 2 compression rings):

CYL 1
top ring - 0.008 top / 0.009 bottom
2nd ring - 0.012 top / 0.011 bottom

CYL 2
top ring - 0.018 top / 0.019 bottom
2nd ring - 0.007 top / 0.006 bottom

CYL 3
top ring - 0.016 top / 0.017 bottom
2nd ring - 0.010 top / 0.008 bottom

CYL 4
top ring - 0.010 top / 0.011 bottom
2nd ring - 0.008 top / 0.007 bottom

Looks like the top rings on CYL 2 & 3 are too much? based on the service manual specs they are out of the standard value range...but within the serviceable limit (see table below for reference)?

Correct me if I'm wrong but is the "serviceable limit" the very maximum the gap should be before replacing?

If anything I thought the gaps would have been tight making it difficult for the pistons to move when installing into the jugs.

What are your opinions?

Thanks, Fraser

[Fraserimoore]

Sorry I'm from the UK, readings are metric which I believe are matching the numbers in the brackets from the gap table?...I hope so anyway?

I used my feeler gauge which both have metric and imperial readings, but being a limey I prefer metric.

[BomberMann650]

The follow up question - where does that measure come from?

[Fraserimoore]

Placing each ring at the top and bottom of the cylinder

[BomberMann650]

Placing each ring at the top and bottom of the cylinder

Okay thanks, learning new stuff! YEAH!